Amazons dynamodb（通过aws sdk）有一个很好的对象映射器可以在nodejs中使用吗？

Question

Maybe the question does not apply to dynamoDB due to it not being Relational Db. However, I'm looking for a good object mapper which can be used in nodejs and aws sdk to map existing model classes to dynamoDB tables. Does anyone have experience with this issue/question, or have you used such a module/library?

Answer 1

If you are looking for schema:

• https://github.com/clarkie/dynogels (well supported forked from vogels which has been abandoned )
• https://github.com/automategreen/dynamoose (inspired by Mongoose )

If you are looking for something to throw javascript objects (even circular graphs) to:

• https://github.com/aaaristo/dyngodb (alpha)
• https://github.com/aaaristo/angular-gson-express-dyngodb

dyngodb has experimental support for full-text search, and transactions too.

Both are based on aws-sdk.

Answer 2

Also worth considering is simple marshallers, which just translate between the dynamoDB format and regular js objects or JSON.

DynamoDb-Data-Types
https://github.com/kayomarz/dynamodb-data-types
https://www.npmjs.com/package/dynamodb-data-types

"This utility helps represent AWS DynamoDb data types. It maps (marshalls) JavaScript data into the format required by DynamoDb."

dynamoDb-marshaler
https://github.com/CascadeEnergy/dynamoDb-marshaler https://www.npmjs.com/package/dynamodb-marshaler

"Translates sane javascript objects (and JSON) into DynamoDb format and vice versa." [does not support B type.]

Update 2016-06 :
Just discovered that the AWS SDK now does this for you. Their documentation is only partially converted so I guess this is a recent addition. Read about it here .

But these marshallers are still useful because there are circumstances where you can't use the new document client, eg. when processing a dynamoDB stream.

Answer 3

You could also try: https://dynamoosejs.com/ . It is inspired by mongoose again.

Answer 4

If you are using Typescript, dynamo-easy might be a good option. Just add some decorators to your model and start using it.

import { Model, PartitionKey, DynamoStore } from '@shiftcoders/dynamo-easy'

@Model()
export class Person {
  @PartitionKey()
  id: string
  name: string
  yearOfBirth: number
}

const personStore = new DynamoStore(Person)

personStore
  .scan()
  .whereAttribute('yearOfBirth').equals(1958)
  .exec()
  .then(res => console.log('ALL items with yearOfBirth == 1958', res))

It uses the AWS DynamoDB sdk but takes care of the mapping between JS and DynamoDB types and provides a simple to use fluent API.

full disclosure: I am one of the authors of this library

Answer 5

After looking over all the posts I landed on https://github.com/awspilot/dynamodb-oop

It doesn't hide the API but instead just wraps it in a nice, fluent way with promises even and you inject your version of the aws-sdk. It's similar to dynamodb-data-types but also wraps the methods too (not just the data types).

Extra bonus, the same author has https://github.com/awspilot/dynamodb-sql Didn't use the sql wrapper but I can see how some people may prefer that.

Dynamoose is obviously inspired by mongoose and is a good choice if you have a well-defined schema and/or want to be abstracted away from the DynamoDB details.

Answer 6

Have you seen dynasaur ? It seems to be the type of thing you're looking for, but I have not used it myself. There's also dynamodb-data-types which is not an ORM, but makes it easy to convert to/from standard JavaScript objects.